1. Field of the Invention
This invention relates to sign structures, illuminated or not, and in particular to a sign cabinet having a scroll which is automatically indexed past the sign face opening.
2. Description of the Prior Art
There are available sign cabinets or display units having a scroll-like sign face. Such structures are used to selectively display a multiplicity of messages, advertisements, etc. Typical scroll-type sign structures advance the scroll from one message to another under the control of an operator. Examples of such structures are shown in U.S. Pat. Nos. 3,614,727 and 3,761,890, respectively issued Oct. 19, 1971, to Fritts and May 25, 1972, to Fritts et al., both of which are assigned to the assignee of the present invention.
U.S. Pat. No. 3,678,282 issued July 18, 1972, to Johnson et al., describes a photocell-controlled circuit which is used for moving a film strip back and forth between the ends of the strip and stopping at frames on the strip. One or two motors drive the film strip through a differential unit. A system of brakes and clutches is used to maintain tension across the film strip. As will be appreciated, this arrangement is relatively complicated and expensive, and, as mentioned, its operation is limited to moving the strip between its endpoints.
Accordingly, it is highly desirable to have a scroll-type sign structure which has the versatility of operating in a variety of modes, yet, is durable, and relatively uncomplicated and inexpensive.